PLANNING CONJUNCTIVE USE PRACTICES - A ...

PLANNING CONJUNCTIVE USE PRACTICES A PREREQUISITE FOR IRRIGATION DEVELOPMENT IN INDIA Pradeep K. Naik, Bhushan Lamsoge, and Deepak Y. Sirsikar Scientists, Central Ground Water Board, Central Region, Nagpur ABSTRACT

Water is man’s most vital resource. However, the rapid pace of water resources development during the past five decades has led to a myriad of problems. For example, most of the Command areas of major and medium irrigation projects suffer from water logging and/or soil salinity problems. In this contribution, an attempt has been made to emphasize the need of conjunctive use practices in the irrigation Command areas on the basis of the actual field studies carried out in the Koyna, Krishna and Nira River basins in the District of Satara, State of Maharashtra. Ground water levels in these areas are generally found within 3 metres below ground level (mbgl) with minimal seasonal fluctuations. Ground water levels are also rising alarmingly in most parts of these Command areas. Soils have already started showing salt encrustations, water quality shows high salinity hazards, and productivity of crops has reduced drastically. Such is generally the case in most of the canal Command areas in National scenario. Recognizing the crucial importance of the conjunctive use practices, Government of India thought it necessary to take up few state-of-the-art conjunctive use studies distributed all across the country. The task was entrusted to Central Ground Water Board (CGWB), Ministry of Water Resources, Government of India. CGWB took up conjunctive use feasibility studies in six Command areas between the years 1990 and 1996 under different hydrogeological environments in the States of Uttar Pradesh, Rajasthan, Andhra Pradesh, Karnataka, Orissa and Gujarat separately. Each of these projects included detailed studies of the Command areas in terms of water logging, soil salinity, hydrogeological surveys, mathematical modelling, data analyses and economic appraisal. The findings of the work done by CGWB in these canal Command areas are also summarised in this paper. Results indicate that economically feasible conjunctive use projects are possible, and can be successfully implemented to achieve optimum results in water resources management practices in the irrigation sector. INTRODUCTION Conjunctive use implies the planned and co-ordinated harnessing of ground water and surface water resources in order to achieve optimum utilization of total water resources (Karanth, 1999). With the population in the country crossing one billion marks, the future demand of water supply cannot be entirely met with either by surface water or ground water resources. It is in this context that joint operation and economic use of surface water and ground water through coordinated development and economic utilization, i.e., conjunctive use, becomes essential. This paper emphasizes the need of planning conjunctive use practices, especially in the canal Command areas, taking examples from Satara District of Maharashtra State, and presents the results of few stateof-the-art case studies taken up by Central Ground Water Board (CGWB) in different parts of the country. 1

Conjunctive use is a diversified term that includes several applications in water resources sector. Apart from the water logging problems, irrigation management, and salinity control, it has much wider applications such as drought control, artificial recharge to ground water, salt balancing by dilution method in salinity affected areas, inter-basin transfer of waters, etc. Thus, ground water can be used to supplement surface water supplies to reduce peak demands for irrigation and other uses, or to the meet deficits in the years of low rainfall. On the other hand, surplus surface water can be used in overdraft areas to increase the ground water storage by artificial recharge. Surface water, ground water or both, depending on the surplus available, can be diverted from areas of plentiful water to areas of deficit water. PLANNING CONJUNCTIVE USE PRACTICES – THE NEED The importance of conjunctive use practices has been emphasized on the basis of the actual field studies conducted by Central Ground Water Board in Satara District of Maharashtra State (Fig. 1). This district is bounded by the Western Ghats hill ranges in the western part from where many large rivers such as the Nira, Krishna, and Koyna from north to south have originated. The narrow winding valleys of the Western Ghats region offers ample opportunity for construction of small to large-sized dams for retention of surface runoff. Several irrigation projects have already been constructed in these areas in recent years, and irrigation is practiced through canal systems in these projects. Agricultural productivity has dramatically increased. Areas, which were once dry or could sustain only one seasonal crop, are now full of lush greenery throughout the year. Cash crops such as sugarcane that needs continuous watering for a prolonged period has become the favorable crop. However, these developments have created two side effects: (1) there is a growing economic disparity in the region; farmers in the canal Command areas are prospering while their counterparts in the non-command areas are still very poor, and (2) because canal water is available at cheap rates, often subsidized by the government, farmers tend to rely more on surface water than on groundwater. As a result, many low-lying areas are being water logged due to over-application of water. These issues call for a better water resources management including conjunctive use of water resources in the canal Command areas and augmentation of groundwater in the water scarce areas through artificial recharge measures. Examples of three medium irrigation projects have been considered to show as to why the conjunctive use practices have become so important for this district. Similar is generally the case in most of the canal Command areas elsewhere in the country, especially in hard rock terrains. Satara district is simply an example to represent these areas. The salient features of the three irrigation projects considered here are given in Table 1. Dias (1977, 1982) and Bhaisare (1979) carried out hydrogeological investigations in the Nira River basin during the years 1974-75, 1975-76 and 1977-78 respectively. They found the depth to ground water levels (DTW) to be varying between 3-6 m below ground level (mbgl) around Lonand-Taradgaon area west of Phaltan and also in the non2

command areas of the Nira Left Bank Canal (NLBC) originating from the Vir River Project. They also found a DTW of less than 3 mbgl in the NLBC Command areas. Naik (1996) carried out hydrogeological studies in the same area during the water year 199192 and found the DTW to be varying between 6 to more than 9 mbgl in the noncommand areas including the Lonand-Taradgaon areas. On the other hand, DTW either remained stable or rose significantly in the canal Command areas in between these two periods. Water logging in the Nira Command area is a known case where salinity of ground water has increased significantly and productivity of cash crops such as sugarcane has decreased. Electrical conductivity varies in this area between 3600 µmhos/cm at Pimpalwadi and 6100 µmhos/cm at Somanthali north of Phaltan. Table 1. Salient features three major irrigation projects in Satara District, Maharashtra. Vir Dhom Koyna Type of Dam Earthern Earthern Masonry Height (m) 35.82 50 85.35 Length (m) 3503.67 2478 807.72 2 Catchment area (km ) 1736 217.56 954.20 Storage (MCM) (a) Gross 278 382 2797 (b) Live 266 331 2678 Canal Length (km) (a) LBC 161 113 + 235 (Arphal) (b) RBC 168 59 Command Areas (a) LBC 24825 + 31005 (Arphal) 16590 (b) RBC 55061 (Total) 8100 Similarly, Das and Sudarshana (1985) found the DTW to be more than 6 m around Rahimatpur area south of Koregaon and less than 3 m in the vicinity of Krishna River in the year 1979-80. Studies by Naik (1996) indicated widening of these DTWs during the water year 1991-92 showing decline and rise of ground water levels in these respective areas – decline due to over-exploitation and rise due to accrual of surface water due to over-application of lift-irrigation water from the Krishna River. DTW became less than 3 m around Koregaon area due to over-application of canal water from the Dhom Irrigation Project after the canal systems became operational in early 90s. Groundwater irrigation decreased 40% in Koregaon Taluka from 5443 ha in 1985-86 to 3240 ha in 1991-92, and surface water irrigation increased 440% from 1578 ha in 198586 to 8523 in 1991-92 in a span of just five years. These statistics indicate that conjunctive use practices need to be initiated in the Dhom Canal Command areas from now itself before things aggravate and it becomes another case study for water logging problems. The Koyna River Project is basically a hydro-electric project, and is not designed for irrigation purposes. However, after the Koyna earthquake of 1967, water is released two times in a month from this dam to reduce stress on the dam due to overloading. Koyna River is now a perennial river due to such release of water from the dam (Fig. 1). About 61 MCM of surface water is lifted annually from this river by farmers for 3

irrigation purposes through several cooperative lift-irrigation schemes (LIS) (Naik and Awasthi 2003). Farmers usually practice flooding method of irrigation while watering their fields. Because they have to wait for a long period, often more than a month, for their turn to come for irrigation, whenever their turn comes they apply as much water as their lands can hold. This practice causes unnecessary wastage of surface water. Assuming that 30% of the applied irrigation water augments the groundwater table (CGWB, 1998), an amount of 18 MCM recharges annually to the Koyna River basin for an application of 61 MCM of surface water. But unfortunately, since minimal quantity of groundwater is actually being utilized, such an accrual of groundwater makes the water table shallower thus leading to water logging to near water logging conditions. Salt encrustations are already seen in the lower reaches, and productivity of crops in these areas has significantly declined. Strong measures, therefore, need to be taken immediately before the lands become permanently unclamable. Conjunctive use of water resources seems to be an easy remedy. The use of surface water resources is not so far regulated. To initiate this process, it would possibly be proper to start metering the quantum of surface water supplied to an individual farmer, or a group of farmers. But this is something not very easy to practice at the present set-up. In case of LIS, such as in the Koyna River basin and elsewhere along the Krishna River, metering at the pumping stations itself and charging accordingly to the cooperative society handling the particular LIS would put pressure on the society itself to regulate its water use. At the moment, individual farmers are charged as per the acreage of land they irrigate, not as per the quantum of water they actually consume. This is a major flaw in the LIS, and once tackled, part of the water logging problem could possibly be solved in the affected areas. For the canal command areas, Government of Maharashtra (GOM) has issued a resolution in July 2001 notifying that irrigation water is to be supplied only to farmers’ Water User Associations (WUAs). Under the WUAmanaged irrigation systems, distribution of water is usually rotated with farmers at the farthest reaches of the command area getting the first share. Since the management is local, the system is transparent. But the GOM’s desire has received limited acceptance among the farmers so far. Mitigation of water logging problems would really get a new boost with the formation of such WUAs in the canal Command areas. One solution to motivate farmers to use appropriate quantity of surface water would be to allow night time irrigation. This will shorten the length of the irrigation cycle. However, night time irrigation might give rise to more uncontrolled irrigation. But, at the moment when the day time irrigation is not well controlled, the issue of controlling the night time irrigation does not arise at all. Therefore, until the time the farmers are not made conscious of the consequences of the irregulated use of water, night time irrigation is an option the authorities might possibly consider to reduce the water use problems. Incentives given to farmers for irrigating their lands through ground water in canal/LIS Command areas are very meagre. Farmers usually get surface water at a very nominal cess rate, often subsidized by the Government. Although a farmer irrigates his land through groundwater for free, he has to pay high bills for electricity, plus the maintenance cost of his well installations, such as a 5 horse power centrifugal pump, pipe lines etc. He has even to take care of the field bundings that he has constructed for easy 4

and controlled irrigation. Except the independence that he gets to irrigate his land at per his will, groundwater irrigation actually becomes costly for a farmer compared to surface water irrigation. In case of surface water irrigation, farmers only have to worry for the timing of the irrigation cycle, nothing else. Since he uses flooding method of irrigation, he is not worried about the development of his field bundings; it actually becomes optional and depends on the individual farmer concerned, and the type of crops he is irrigating. Therefore, putting pressure on the farmers on their water use by metering the water supplied at the point of delivery and at few points in the field would at least make the farmers conscious of water use. By offering incentives in the form of subsidies will encourage farmers to adopt ground water irrigation in the canal/LIS Command areas. FEASIBILITY OF CONJUNCTIVE USE PRACTICES - FEW CASE STUDIES Realizing the importance of the conjunctive use of surface water and ground water in general and in the canal Commands in particular, Govt. of India sanctioned six conjunctive use projects to Central Ground Water Board (CGWB) in different parts of the country (Fig. 2). These projects are (1) Indira Gandhi Nahar Pariyojana Stage-I, Rajasthan, (2) Sharda Sahayak Irrigation Project, Uttar Pradesh, (3) Tungabhadra Irrigation Project, Andhra Pradesh and Karnataka, (4) Ghataprabha Irrigation Project, Karnataka, (5) Hirakund Irrigation Project, Orissa and (6) Mahi – Kadana Irrigation Project, Gujarat. The salient features of these conjunctive use projects are given in Table 2. Table 2. Salient features of conjunctive use projects executed by CGWB during 1990-96. Sharda IGNP-I Tungabhadra GhataHirakund MahiSahayak prabha Kadana Objectives Water Water Water Water Flood water level rise, logging logging logging, soil logging control, soil salinity water level rise salinity Area (km2) 8978 4790 6354 10370 1570 3717 Area affected (km2) a) Waterlogged 4874 5250 130 580 174 0.8 b) Saline area 255 1730 670 nil nil ---Area selected 8287.5 26450 6354 ------7500 for modeling (km2) Ground water 3063 992 499 599 400 921 potential(MCM) Surface water 2178 4215 1611 ----------2259 potential(MCM) Ground water 906 34 71 361 ---528 draft (MCM) Additional 21375 10023 8285 20619 17526 1164 wells constructed 5

CGWB carried out these studies between the years 1990 and 1996 with the following objectives. 1) To evaluate the surface water and ground water resources available in space and time so as to determine the water balance. 2) To identify the critical areas of water logging and soil salinity as well as scarcity areas within the Command areas. 3) To match the demands of various sectors with the available water resources and to evolve a strategy to meet the projected demands of the future. 4) To mathematically model the study areas in order to simulate the hydrogeological situations and various other scenarios to evolve strategies for optimum development of the ground water resources. 5) To formulate suitable plans for controlling the problem of rising water levels. 6) To examine the sustainability of the present irrigation practices with respect to conjunctive use of water resources and suggest improvements for the future. 7) To evaluate the economic aspects of ground water development plans with respect to cost-benefit ratio, internal rate of return and pay back period etc. The studies in detailed are illustrated in a special issue of Bhujal News, Vol. 14, No. 1 and 2, 1999, published by Central Ground Water Board, Ministry of Water Resources, Government of India. The following measures were suggested in general by CGWB for planning conjunctive practices in the canal Command areas. 1. An economically feasible conjunctive use plan can be formulated and can be implemented successfully. 2. Ground water use needs to be encouraged in Command areas along with surface water by increasing the scope for ground water development. 3. For implementing ground water development plans, experienced ground water scientists need to be employed to pinpoint sites for installing production wells. All the well sites are to be located strictly within the ground water potential zones and follow the well spacing norms on scientific basis. 4. Monitoring of ground water regime as well as surface water should be a continuous process. 5. The quantification of surface water and ground water resources in the Command areas needs to be revised in every five years. The situation of water logging should be reexamined. If necessary, ground water draft can be stepped up to reduce water logging problems. 6. Mathematical models for the affected areas need to be developed for devising planning options for better and optimal performance. 7. Farmers’ involvement as co-operative movement is pragmatic, and Farmers Managed Irrigation System (FMIS) should be adopted instead of Government Managed Irrigation System (GMIS).

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8. The existing cropping pattern may need modification. For example, diversification of crops from paddy to non-paddy is necessary in some problematic areas. 9. More meteorological stations may be established within the Command areas to record hydrometeorological parameters, such as rainfall, temperature, humidity, evaporation etc. 10. The National Scenario of conjunctive use programme suggests that what is being practiced in the country at the moment does not really envisage the optimal use of both surface water and ground water resources. Most of the major irrigation projects have been designed, keeping in view only the surface water inputs; utilization of ground water is being thought of only after problems of water logging, salinisation etc. are caused in the canal Commands. National Water Policy (1987) directs that both surface water and ground water be viewed as an integrated resource and be developed conjunctively in coordinated manner and that their use be envisaged right from the project planning stage itself to avoid problems of water logging and/or soil salinity. SUMMARY AND CONCLUSIONS Examples from Satara District in Maharashtra State show that conjunctive use practices are an inevitable prerequisite for integrated development of both surface water and ground water resources in canal/lift irrigation (LI) Command areas. Much of the rising water levels, water logging and soil salinity and also water scarcity problems in the irrigation Commands could be solved through conjunctive use practices. Some kind of a regulation to force farmers to use ground water as part of their water requirements could possibly help in controlling the rising water table in canal/LI Command areas. Most water use problems are due to increased length of the irrigation cycle and flooding method of irrigation practices. Because farmers have to wait for a long period for their turn to come for irrigation, whenever their turn comes, they apply as much water as their fields can hold. This practice causes unnecessary wastage of surface water. To check the use of water it would probably be better to start metering the quantum of water supplied to an individual farmer or a group of farmers. Farmers may be charged cess rates as per the quantum of water they actually use instead of the acreage of land they irrigate. Government of Maharashtra has already tried to introduce a new system in which irrigation water is to be supplied only to farmers’ Water Use Associations (WUAs). Once this system becomes popular much of the water use problems could be solved, since the distribution of canal water will be managed by farmers themselves. At present, ground water irrigation is costlier than surface water in the irrigation Commands. Government should possibly try to introduce some schemes in the form of subsidies to encourage farmers to adopt ground water irrigation in the canal/LI Command areas. Case studies by Central Ground Water Board in six different canal Command areas across the country indicate that an economically feasible conjunctive use plan can be formulated and can be implemented successfully. Strict measures need to be framed to plan conjunctive use practices from the project planning stage itself to adhere to the National Water Policy (1987, 2002).

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The concept of conjunctive use practices is so far confined only to mitigation of water logging/soil salinity problems. Conjunctive use may be practiced to tackle declining trends of ground water levels in most parts of the country by transporting water from water surplus areas to water deficit areas. This practice, hence, can be used for artificial recharge of aquifers, which is the call of the Nation today. REFERENCES Bhaisare AR (1979) Systematic hydrogeological studies in parts of Nira Sub-basin, Central Ground Water Board, Central Region, Nagpur CGWB (Central Ground Water Board) (1984) Report of the ground water estimation committee (GEC – 1997), Central Ground Water Board, Ministry of Water Resources, Government of India, New Delhi. Das S and Sudarshana SS (1985) Systematic hydrogeological studies in parts of Krishna Basin, Central Ground Water Board, Central Region, Nagpur Dias JP (1977) Hydrogeological studies in parts of Nira Sub-basin, Central Ground water Board, Central Region, Nagpur Dias JP (1982) Hydrogeological studies in parts of Nira Sub-basin, Central Ground Water Board, Central Region, Nagpur Karanth KR (1999) Ground water assessment, development and management, Tata McGraw Hill, New Delhi, 720 pp Naik PK (1996) Reappraisal hydrogeological surveys in parts of Satara District, Maharashtra, Central Ground Water Board, Central Region, Nagpur Naik PK and Awasthi AK (2003) Groundwater Resources Estimation of the Koyna River basin, India. Hydrogeology Journal 11(5): 582-594

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Command area

Fig.1. Locations of three Irrigation Projects in Satara District, Maharashtra

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Fig. 2. Locations of Conjunctive use Projects in India executed by Central Ground Water Board

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